The present invention relates to a numerical control device for processing machines, such as machine tools, for example, which control device includes a computer, a memory unit and an input unit for programming machine functions.
In conventional numerically controlled machine tools it is common practice according to Deutche Normen DIN 66025 to code additional machine functions, such as "Coolant on/off", or "Spindle Turning Direction left/right" by means of the address letter M and a two-digit number. Feed rates are generally coded by means of the address letter F followed by a two-digit number. Frequently, feed rates are encoded as the address letter F and the feed rate in millimeters per minute. When such control codes are used the operator may often be called on to retain a very large number of code symbols in his memory, which may lead to operational errors.
In West German unexamined patent specification OS. No. 1,928,996 a numerical control for machine tools is described in which such operating information is entered by means of coded keys of a hand input device which simultaneously stores the selected code on punched strips. After the processing of a first workpiece, the punched strip is then fed into a reading or control apparatus in order to control the machine tool and produce further workpieces of the same type. In this device the operator must have programming experience in order to properly use the input device.